Lucius was a Death Eater during Voldemort's first "reign of terror," however after he disappeared, Malfoy "came back saying he'd never meant any of it". Arthur Weasley reportedly believes that Malfoy was in Voldemort's "inner circle".
Lucius revived his old allegiances when Voldemort rose to power once again. He has a variety of illegal poisons, Dark Arts objects and artifacts hidden in his mansion, some in a secret chamber under the dining room floor. He is strongly against admitting non-pureblood witches and wizards into Hogwarts and he uses his influence to try to force changes there.
He considers Dumbledore to be a very poor headmaster and even succeeded in getting him temporarily removed from that position.
The Malfoys had a house-elf named Dobby who was "bound to serve one house and one family forever" until Harry tricked Lucius into releasing him.
Lucius Malfoy has used his position in the Wizarding community and well-placed donations and contributions to gain considerable power in the current Ministry of Magic. Fudge acquiesces to Lucius, impressed with the "purity" of his Wizarding blood and sizable sums of Galleons he donates.
After retaking his place as a Death Eater on June 24, 1995, Lucius participated in the attack on Harry in the graveyard of Little Hangleton. When that didn't go as planned but Harry wasn't believed, he resumed his privileged position with respect to the Ministry, especially influencing Fudge. Lucius was solidly a Death Eater, however, and he fought in the battle in the Department of Mysteries. He was captured and has been sent to Azkaban.
Lucius Malfoy has white hair and a pale, pointed face with cold, gray eyes. He was 41 years old in the fall of 1995, which means he was probably born in 1954.
Chez Dumbledore